Kcli Provider Development

kcli Provider Development

Provider Architecture

Providers are located in kvirt/providers/ as subdirectories. Each provider implements the interface defined in kvirt/providers/sampleprovider.py (class Kbase).

Required Implementation Steps

1. Create Provider Directory

kvirt/providers/yourprovider/
├── __init__.py      # Contains your Kyourprovider class
└── (optional helpers)

2. Implement the Provider Class

Your class must:

• Set self.conn attribute in __init__ (set to None if backend unreachable)
• Set self.debug from the debug parameter
• Return standardized response dicts from methods

Return Value Pattern:

# Success
return {'result': 'success'}

# Failure
return {'result': 'failure', 'reason': "VM %s not found" % name}

3. Core Methods to Implement

VM Lifecycle (required):

• create() - Create VM with all parameters (cpus, memory, disks, nets, etc.)
• start(name) - Start VM
• stop(name, soft=False) - Stop VM
• restart(name) - Restart VM (default calls start)
• delete(name, snapshots=False, keep_disks=False) - Delete VM
• list() - Return list of [name, state, ip, source, plan, profile]
• info(name, output, fields, values, vm, debug) - Return VM details dict
• exists(name) - Check if VM exists
• status(name) - Return VM status
• ip(name) - Return IP string
• clone(old, new, full=False, start=False) - Clone VM
• export(name, image=None) - Export VM as image
• console(name, tunnel, tunnelhost, tunnelport, tunneluser, web) - Graphical console
• serialconsole(name, web) - Serial console

Storage:

• create_pool(name, poolpath, pooltype, user, thinpool)
• delete_pool(name, full)
• list_pools() - Return list of pool names
• get_pool_path(pool) - Get pool path
• add_disk(name, size, pool, thin, image, shareable, existing, interface, novm, overrides)
• delete_disk(name, diskname, pool, novm)
• create_disk(name, size, pool, thin, image) - Create standalone disk
• list_disks() - Return dict {'diskname': {'pool': poolname, 'path': name}}
• disk_exists(pool, name) - Check if disk exists
• detach_disks(name) - Detach all disks from VM

Networking:

• create_network(name, cidr, dhcp, nat, domain, plan, overrides)
• delete_network(name, cidr, force)
• update_network(name, dhcp, nat, domain, plan, overrides)
• list_networks() - Return dict of networks
• info_network(name) - Get network info
• net_exists(name) - Check if network exists
• network_ports(name) - List ports on network
• add_nic(name, network, model)
• delete_nic(name, interface)
• update_nic(name, index, network) - Update NIC

Subnets (cloud providers):

• create_subnet(name, cidr, dhcp, nat, domain, plan, overrides)
• delete_subnet(name, force)
• update_subnet(name, overrides)
• list_subnets() - Return subnet dict
• info_subnet(name) - Get subnet info

Images:

• volumes(iso=False, extended=False) - List available images
• add_image(url, pool, short, cmds, name, size, convert)
• delete_image(image, pool)

Snapshots:

• create_snapshot(name, base) - Create snapshot
• delete_snapshot(name, base) - Delete snapshot
• list_snapshots(base) - List snapshots (returns list)
• revert_snapshot(name, base) - Revert to snapshot

Update Operations:

• update_metadata(name, metatype, metavalue, append)
• update_memory(name, memory)
• update_cpus(name, numcpus)
• update_start(name, start) - Set autostart
• update_information(name, information) - Update info metadata
• update_iso(name, iso) - Change attached ISO
• update_flavor(name, flavor) - Change VM flavor

Buckets (object storage):

• create_bucket(bucket, public) - Create storage bucket
• delete_bucket(bucket) - Delete bucket
• list_buckets() - List all buckets
• list_bucketfiles(bucket) - List files in bucket
• upload_to_bucket(bucket, path, overrides, temp_url, public)
• download_from_bucket(bucket, path)
• delete_from_bucket(bucket, path)

Security Groups (cloud providers):

• create_security_group(name, overrides)
• delete_security_group(name)
• update_security_group(name, overrides)
• list_security_groups(network) - List security groups

DNS:

• reserve_dns(name, nets, domain, ip, alias, force, primary, instanceid)
• list_dns_zones() - List DNS zones
• dnsinfo(name) - Return (dnsclient, domain) for VM

Other:

• close() - Clean up connection
• info_host() - Return host info dict
• vm_ports(name) - List ports on VM
• list_flavors() - Return [[name, numcpus, memory], ...] if platform supports flavors

4. Register Provider in config.py

Add import and instantiation in kvirt/config.py (around lines 102-220):

elif self.type == 'yourprovider':
    # Get provider-specific options
    option1 = options.get('option1')
    if option1 is None:
        error("Missing option1 in configuration. Leaving")
        sys.exit(1)
    try:
        from kvirt.providers.yourprovider import Kyourprovider
    except Exception as e:
        exception = e if debug else None
        dependency_error('yourprovider', exception)
    k = Kyourprovider(option1=option1, debug=debug)

5. Add Dependencies to setup.py

YOURPROVIDER = ['required-package1', 'required-package2']

# Add to extras_require dict:
extras_require={
    'yourprovider': YOURPROVIDER,
    # ...
}

# Add to ALL list if needed:
ALL = EXTRAS + AWS + ... + YOURPROVIDER

Info Method Structure

The info() method should build a dict with these keys:

• name, autostart, plan, profile, image, ip, memory, numcpus, creationdate
• nets: list of {'device': device, 'mac': mac, 'net': network, 'type': network_type}
• disks: list of {'device': device, 'size': disksize, 'format': diskformat, 'type': drivertype, 'path': path}
• snapshots: list of {'snapshot': snapshot, 'current': current}

Then call: common.print_info(yamlinfo, output=output, fields=fields, values=values)

Reference Implementations

Study these existing providers:

• kvirt/providers/kvm/ - Libvirt (most complete reference, ~4300 lines)
• kvirt/providers/aws/ - AWS cloud (~2200 lines)
• kvirt/providers/gcp/ - Google Cloud Platform (~2100 lines)
• kvirt/providers/kubevirt/ - KubeVirt on Kubernetes (~1900 lines)
• kvirt/providers/vsphere/ - VMware vSphere (~1900 lines)
• kvirt/providers/azure/ - Microsoft Azure (~1500 lines)
• kvirt/providers/ibm/ - IBM Cloud (~1500 lines)
• kvirt/providers/ovirt/ - oVirt/RHV (~1400 lines)
• kvirt/providers/openstack/ - OpenStack (~1350 lines)
• kvirt/providers/proxmox/ - Proxmox VE (~1200 lines)
• kvirt/providers/hcloud/ - Hetzner Cloud (~550 lines)
• kvirt/providers/web/ - Web-based provider (~530 lines)
• kvirt/providers/fake/ - Minimal stub for testing (~20 lines)

Provider Complexity Guide

Not all providers need to implement every method. Focus on:

1. Minimum viable: create, delete, list, info, start, stop, exists, status, ip
2. Storage: add_disk, delete_disk, list_disks, create_pool, delete_pool, list_pools
3. Networking: create_network, delete_network, list_networks, net_exists
4. Images: volumes, add_image, delete_image
5. Advanced: Snapshots, cloning, export, buckets, security groups (as needed)

Methods can return {'result': 'success'} with a print("not implemented") for optional features.

Source: karmab/kcli — distributed by TomeVault.